1. Field of the Invention
The present invention relates to an image-processing computer system for a photogrammetric analytical measurement, in which a survey map is electronically produced based on a pair of photographed pictures obtained at two different photographing positions.
2. Description of the Related Art
For example, photogrammetry is carried out at a traffic accident spot. The traffic accident spot is photographed by an electronic still video digital camera in at least two different positions, and a survey map of the traffic accident spot is produced based on a pair of photographed pictures obtained at the different positions, as disclosed in, for example, Unexamined Japanese Patent Publications No. 10-221072 and No. 10-293026.
Before accurately scaled distances and lengths can be reproduced on the survey map, a standard measurement scale or target must be recorded together with the photographed objects in the pictures. The target is disclosed in, for example, Unexamined Japanese Patent Publications No. 10-141951, No. 10-170263, No. 10-185562, No. 10-185563, No. 10-293026, No. 10-307025 and No. 11-295065.
For the production of the survey map, a two-dimensional coordinate system is defined on each of the pictures, and two-dimensional positions of the objects, which are recorded on each picture, are determined by the two-dimensional coordinate system. Also, a three-dimensional coordinate system is defined on the target, and three-dimensional positions of the recorded objects are determined based on the two-dimensional positions of the objects with respect to the three-dimensional coordinate system. Accordingly, it is possible to produce a survey map by projecting the three-dimensional coordinates, representing the objects, on one of the three planes defined by the three-dimensional system. Of course, the production of the survey map is performed using an image-processing computer system.
For example, to produce a long portion of a roadway as a survey map, it is necessary to obtain plural pairs of pictures to cover the length of the roadway, and the target must be moved from one position to another position in the length of the roadway. In this case, a survey map section is produced based on each pair of pictures, and the survey map is obtained by successively connecting the survey map sections to each other. Of course, the production of all the survey map sections must be united with respect to a single three-dimensional coordinate system defined on the target located at a previously-selected position. Thus, when the plural pairs of pictures are processed using the image-processing computer system by an operator to produce the survey map, it must be always known by the operator which target position each pair of pictures features and where each picture is photographed, resulting in facilitation of the production of the survey map. However, in reality, it is difficult to visually recognize the circumstances of a picture among other many pictures.